Fig. 3

Lateral radiographs and MRIs of the thoracic spine in the three siblings. a In Patient 1, lateral thoracic spine radiograph (left) at 10 years of age shows relatively moderate vertebral body height loss (platyspondyly) and anterior vertebral body beaking, most prominent in the mid-to-lower thoracic spine (arrowheads). Sagittal T2-weighted MRI of the thoracic spine (right) shows moderate platyspondyly with prominent anterior beaking of multiple thoracic and upper lumbar vertebral bodies (arrowheads). The patient was initially diagnosed with spondyloepiphyseal dysplasia on the basis of clinical presentation, platyspondyly, and femoral epiphyseal abnormalities on imaging, although anterior beaking in the middle third of the spine is highly suggestive of MPS IVA, and vertebral flattening is not as prominent as would be expected in spondyloepiphyseal dysplasia. b In Patient 2, lateral thoracic spine radiograph at 6 years of age (left) shows anterior beaking of multiple thoracic vertebral bodies (arrowheads). Sagittal T2-weighted MRI of the thoracic spine at 10 years of age (right) shows anterior vertebral body beaking (arrowheads) with mild vertebral height loss without platyspondyly. Presence of anterior vertebral body beaking in this case is strongly suggestive of MPS IVA. c In Patient 3, lateral thoracic spine radiograph at 3 years of age (left) shows anterior beaking of multiple thoracic vertebral bodies without significant vertebral body height loss. Sagittal T2-weighted MRI of the thoracic spine at 5 years of age (right) highlights anterior vertebral body beaking. As with this patient’s siblings, anterior vertebral body beaking supported the diagnosis of MPS IVA